ENHANCED INSULIN-RECEPTOR TYROSINE KINASE-ACTIVITY ASSOCIATED WITH CHROMOSOMAL TRANSLOCATION (1-19) IN A PRE-B-CELL LEUKEMIA LINE
NEWMAN, JD; Harrison, LC; ECKARDT, GS; JACK, I
INTERNATIONAL JOURNAL OF CANCER
The gene for the insulin receptor has been assigned to chromosome 19 near the breakpoint of the translocation t(1;19) which occurs in 25% of pre-B-cell leukemias. Insulin receptors in a pre-B-cell leukemia cell line (ACV) with t(1;19) were found to have 2-fold higher affinity for insulin, 5-fold higher basal and insulin-stimulated beta-sub-unit autophosphorylation, and 2-fold higher basal and 4-fold higher insulin-stimulated beta-sub-unit kinase activity on the synthetic peptide poly(Glu,Tyr), compared to receptors in a B-cell line (ADD) with normal karyotype from the same patient. ACV cells had a novel 13-kb receptor mRNA species and expressed a DNA polymorphism localized to the tyrosine kinase domain of the receptor gene. These findings suggest that t(1;19) in the ACV cell may result in rearrangement of the insulin receptor gene and translation of a receptor with enhanced tyrosine kinase activity.